Varieties[2] of the colorblue may differ in hue, chroma (also called saturation, intensity, or colorfulness), or lightness (or value, tone, or brightness), or in two or three of these qualities. Variations in value are also called tints and shades, a tint being a blue or other hue mixed with white, a shade being mixed with black. A large selection of these various colors is shown below.

The web colorlight blue is displayed in the color box at right. Variations of this color are known as sky blue, baby blue, or angel blue. Within the X11 color system, with a hue code of 194, this color is closer to cyan than to blue.

The first recorded use of "light blue" as a color term in English is in the year 1915.[5]

Shown in the right is the color periwinkle, or periwinkle blue. Another name for this color is lavender blue, the color is a mixture of white and blue. It is named after the Periwinkle flower and is also commonly referred to as a tone of light blue.

The color defined as blue in the RGB color model, X11 blue, is shown at right. This color is the brightest possible blue that can be reproduced on a computer screen, and is the color named blue in X11, it is one of the three primary colors used on the RGB color space, along with red and green. The three additive primaries in the RGB color system are the three colors of light chosen such as to provide the maximum gamut of colors that are capable of being represented on a computer or television set.

The color defined as blue in the CMYK color system used in printing, also known as pigment blue, is the tone of blue that is achieved by mixing process (printer's) cyan and process (printer's) magenta in equal proportions. It is displayed at right.

The purpose of the CMYK color system is to provide the maximum possible gamut of color reproducible in printing by the use of only three primaries.

The color indicated is only approximate as the colors of printing inks may vary.

The hues of the Munsell color system, at varying values, and maximum chroma to stay in the sRGB gamut

The color defined as blue in the Munsell color system (Munsell 5B) is shown at right, the Munsell color system is a color space that specifies colors based on three color dimensions: hue, value (lightness), and chroma (color purity), spaced uniformly (according to the logarithmic scale which governs human perception) in three dimensions in the Munsell color solid, which is shaped like an elongated oval at an angle. In order for all the colors to be spaced uniformly, it was found necessary to use a color wheel with five primary colors: red, yellow, green, blue, and purple.

The Munsell color displayed is only approximate, as these spectral colors have been adjusted to fit into the sRGB gamut; in the 21st century, this hue is classified as an intermediate between azure and cyan.

In this section, the term shade is used in its technical sense as used in color theory, meaning a blueish color mixed with black or dark gray. The colors arranged in order of their value (brightness) (V in the HSV code), the brighter colors toward the top and the darker colors toward the bottom.

Spanish blue is the color that is called Azul (the Spanish word for "blue") in the Guía de coloraciones (Guide to colorations) by Rosa Gallego and Juan Carlos Sanz, a color dictionary published in 2005 that is widely popular in the Hispanophone realm. It is a shade of azure.

Dark blue is a shade of the standard (h = 240°) blue. The name comes from the word "Dark" (which originated from Old English dark, derk, deork; Anglo-Saxondearc, and Gaelic and Irish dorch, dorcha) and "Blue" (taken from French and originated from the Indo-European root bhlewos).

Navy blue is a shade of the standard (h = 240°) blue. Navy blue got its name from the dark blue (contrasted with white) worn by officers in the British Royal Navy since 1748 (originally called marine blue before 1840) and subsequently adopted by other navies around the world.

The first recorded use of navy blue as a color name in English was in 1840.[19]

Dark clothing for males such as black, brown, or dark blue business suits have become much more popular since the mid-1990s, as opposed to the pastel colored business suits worn in the 1970s by major leaders in such institutions as the United States Congress (the vast difference in the clothing worn in the 1970s as opposed to the 2000s (decade) can be readily seen by looking at a videotape of the Watergate hearings).

In Western civilisation, those in the upper classes in high places of political or economic power often wear dark blue suits. Ordinary members of the working class (especially those who work in the computer industry) often refer derisively to these management functionaries as the suits,[27] this terminology is also used in the television industry—the network executives are often referred to by the creative people (actors, directors, and screenwriters) as the suits.[28]

Also, the term blue blood usually refers to the European nobility or upper class, and is based on a medieval belief that the royal blood was blue.[29] In its ironical sense, the term may refer to snobbism and arrogancy.

Dark blue or medium blue can also represent the working class. A blue-collar worker is a member of the working class who typically performs manual labor and earns an hourly wage. Industrial and manual workers wear durable clothing that can be dirty, soiled, or even scrapped at work. A popular element of such clothes has been a light blue or navy blue work shirt and blue is also a popular color for work coveralls, the shirts and coveralls both typically made from denim.

^The color displayed in the color box above matches the color called baby blue in the 1930 book by Maerz and Paul A Dictionary of Color New York:1930 McGraw-Hill; the color baby blue is displayed on page 93, Plate 35, Color Sample E2.

^Color sample #196 on the ISCC-NBS color list is the color sample that matches the color in the book by Maerz and Paul A Dictionary of Color New York:1930 McGraw-Hill--Color Sample of Liberty: Page 109 Plate 43 Color Sample C12

1.
Take Them On, On Your Own
–
Take Them On, On Your Own is the second studio album by American rock Black Rebel Motorcycle Club. It was released in 2003 and reIssued in 2008, the album cover is a homage to the film The Third Man. The album has a darker, harder sound than their debut album. The album reached #3 in the United Kingdom music charts despite receiving mixed reviews, the 2003 release of this album contained the Copy Control protection system in some regions. The Japanese 2008 reIssued CD contains three tracks, Take Them On, On Your Own, High / Low. Additional recording at Exstacy Recording Studios

2.
Blue
–
Blue is the colour between violet and green on the optical spectrum of visible light. Human eyes perceive blue when observing light with a wavelength between 450 and 495 nanometres, which is between 4500 and 4950 ångströms. Blues with a frequency and thus a shorter wavelength gradually look more violet, while those with a lower frequency. Pure blue, in the middle, has a wavelength of 470 nanometers, in painting and traditional colour theory, blue is one of the three primary colours of pigments, along with red and yellow, which can be mixed to form a wide gamut of colours. Red and blue mixed together form violet, blue and yellow together form green, Blue is also a primary colour in the RGB colour model, used to create all the colours on the screen of a television or computer monitor. The clear sky and the sea appear blue because of an optical effect known as Rayleigh scattering. When sunlight passes through the atmosphere, the wavelengths are scattered more widely by the oxygen and nitrogen molecules. An optical effect called Tyndall scattering, similar to Rayleigh scattering, explains blue eyes, distant objects appear more blue because of another optical effect called atmospheric perspective. Blue has been used for art and decoration since ancient times and it is the most important color in Judaism. In the Middle Ages, cobalt blue was used to colour the stained glass windows of cathedrals, beginning in the 9th century, Chinese artists used cobalt to make fine blue and white porcelain. Blue dyes for clothing were made from woad in Europe and indigo in Asia, in 1828 a synthetic ultramarine pigment was developed, and synthetic blue dyes and pigments gradually replaced mineral pigments and vegetable dyes. Pierre-Auguste Renoir, Vincent van Gogh and other late 19th century painters used ultramarine and cobalt blue not just to depict nature, in the late 18th century and 19th century, blue became a popular colour for military uniforms and police uniforms. In the 20th century, because blue was associated with harmony, it was chosen as the colour of the flags of the United Nations. Surveys in the US and Europe show that blue is the colour most commonly associated with harmony, faithfulness, confidence, distance, infinity, the imagination, cold, and sometimes with sadness. In US and European public opinion polls it is the most popular colour, Blue is the colour of light between violet and green on the visible spectrum. Blues also vary in shade or tint, darker shades of blue contain black or grey, darker shades of blue include ultramarine, cobalt blue, navy blue, and Prussian blue, while lighter tints include sky blue, azure, and Egyptian blue. Today most blue pigments and dyes are made by a chemical process, the modern English word blue comes from Middle English bleu or blewe, from the Old French bleu, a word of Germanic origin, related to the Old High German word blao. In heraldry, the azure is used for blue

3.
Wavelength
–
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the waves shape repeats, and thus the inverse of the spatial frequency. Wavelength is commonly designated by the Greek letter lambda, the concept can also be applied to periodic waves of non-sinusoidal shape. The term wavelength is also applied to modulated waves. Wavelength depends on the medium that a wave travels through, examples of wave-like phenomena are sound waves, light, water waves and periodic electrical signals in a conductor. A sound wave is a variation in air pressure, while in light and other electromagnetic radiation the strength of the electric, water waves are variations in the height of a body of water. In a crystal lattice vibration, atomic positions vary, wavelength is a measure of the distance between repetitions of a shape feature such as peaks, valleys, or zero-crossings, not a measure of how far any given particle moves. For example, in waves over deep water a particle near the waters surface moves in a circle of the same diameter as the wave height. The range of wavelengths or frequencies for wave phenomena is called a spectrum, the name originated with the visible light spectrum but now can be applied to the entire electromagnetic spectrum as well as to a sound spectrum or vibration spectrum. In linear media, any pattern can be described in terms of the independent propagation of sinusoidal components. The wavelength λ of a sinusoidal waveform traveling at constant speed v is given by λ = v f, in a dispersive medium, the phase speed itself depends upon the frequency of the wave, making the relationship between wavelength and frequency nonlinear. In the case of electromagnetic radiation—such as light—in free space, the speed is the speed of light. Thus the wavelength of a 100 MHz electromagnetic wave is about, the wavelength of visible light ranges from deep red, roughly 700 nm, to violet, roughly 400 nm. For sound waves in air, the speed of sound is 343 m/s, the wavelengths of sound frequencies audible to the human ear are thus between approximately 17 m and 17 mm, respectively. Note that the wavelengths in audible sound are much longer than those in visible light, a standing wave is an undulatory motion that stays in one place. A sinusoidal standing wave includes stationary points of no motion, called nodes, the upper figure shows three standing waves in a box. The walls of the box are considered to require the wave to have nodes at the walls of the box determining which wavelengths are allowed, the stationary wave can be viewed as the sum of two traveling sinusoidal waves of oppositely directed velocities. Consequently, wavelength, period, and wave velocity are related just as for a traveling wave, for example, the speed of light can be determined from observation of standing waves in a metal box containing an ideal vacuum. In that case, the k, the magnitude of k, is still in the same relationship with wavelength as shown above

4.
SRGB
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SRGB is the standard RGB color space created cooperatively by HP and Microsoft in 1996 for use on monitors, printers and the Internet, and subsequently standardized by the IEC as IEC 61966-2-1,1999. It is often used as the color space for images that do not contain any color space information. This specification allowed sRGB to be displayed on typical CRT monitors of the time. SRGB defines the chromaticities of the red, green, and blue primaries, the gamut of chromaticities that can be represented in sRGB is the color triangle defined by these primaries. SRGB also defines a transformation between the intensity of these primaries and the actual number stored. The curve is similar to the response of a CRT display. It is more important to replicate this curve than the primaries to get correct display of an sRGB image and this nonlinear conversion means that sRGB is a reasonably efficient use of the values in an integer-based image file to display human-discernible light levels. Unlike most other RGB color spaces, the sRGB gamma cannot be expressed as a numerical value. The overall gamma is approximately 2.2, consisting of a section near black, and a non-linear section elsewhere involving a 2.4 exponent. The purpose of the section is so the curve does not have an infinite slope at zero. The CIE XYZ values must be scaled so that the Y of D65 is 1.0 and this is usually true but some color spaces use 100 or other values. The first step in the calculation of sRGB from CIE XYZ is a linear transformation, = It is important to note that these linear RGB values are not the final result as they have not been adjusted for the gamma correction. SRGB was designed to reflect a typical real-world monitor with a gamma of 2.2, and the following formula transforms the linear RGB values into sRGB. If values in the range 0 to 255 are required, e. g. for video display or 8-bit graphics, the values are usually clipped to the 0 to 1 range. This clipping can be done before or after this gamma calculation, again the sRGB component values R s r g b, G s r g b, B s r g b are in the range 0 to 1. Followed by a multiplication of the linear values to get XYZ, = It is often casually stated that the decoding gamma for sRGB data is 2.2. The transformation was designed to approximate a gamma of about 2.2, but with a portion near zero to avoid having an infinite slope at K =0. The continuity condition for the curve C l i n e a r which is defined above as a function of C s r g b, is γ = K0 ϕ

5.
Red
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Red is the color at the longer-wavelengths end of the spectrum of visible light next to orange, at the opposite end from violet. Red color has a predominant light wavelength of roughly 620–740 nanometers, light with a longer wavelength than red but shorter than terahertz radiation and microwave is called infrared. Red is one of the secondary colors, resulting from the combination of yellow. Traditionally, it was viewed as a primary colour, along with yellow and blue, in the RYB color space and traditional color wheel formerly used by painters. Reds can vary in shade from light pink to very dark maroon or burgundy. Red is the color of cyan. In nature, the red color of blood comes from hemoglobin, the red color of the Grand Canyon and other geological features is caused by hematite or red ochre, both forms of iron oxide. It also causes the red color of the planet Mars, the color of autumn leaves is caused by pigments called anthocyanins, which are produced towards the end of summer, when the green chlorophyll is no longer produced. One to two percent of the population has red hair, the color is produced by high levels of the reddish pigment pheomelanin. Since red is the color of blood, it has historically been associated with sacrifice, danger, modern surveys in the United States and Europe show red is also the color most commonly associated with heat, activity, passion, sexuality, anger, love and joy. In China, India and many other Asian countries it is the color of symbolizing happiness, since the 19th century, red has also been associated with socialism and communism. The word red is derived from the Old English rēad, the word can be further traced to the Proto-Germanic rauthaz and the Proto-Indo European root rewdʰ-. In Sanskrit, the word means red or blood. In the Akkadian language of Ancient Mesopotamia and in the modern Inuit language of Inuit, the words for colored in Latin and Spanish both also mean red. In Portuguese the word for red is vermelho, which comes from Latin vermiculus, in the Russian language, the word for red, Кра́сный, comes from the same old Slavic root as the words for beautiful—красивый and excellent—прекрасный. Thus Red Square in Moscow, named long before the Russian Revolution, in heraldry, the word gules is used for red. Red can vary in hue from orange-red to violet-red, and for each hue there is a variety of shades and tints. Red hematite powder was found scattered around the remains at a grave site in a Zhoukoudian cave complex near Beijing

6.
Green
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Green is the color between blue and yellow on the spectrum of visible light. It is evoked by light with a predominant wavelength of roughly 495–570 nm, the modern English word green comes from the Middle English and Anglo-Saxon word grene, from the same Germanic root as the words grass and grow. It is the color of living grass and leaves and as a result is the color most associated with springtime, growth, by far the largest contributor to green in nature is chlorophyll, the chemical by which plants photosynthesize and convert sunlight into chemical energy. Many creatures have adapted to their environments by taking on a green hue themselves as camouflage. Several minerals have a color, including the emerald, which is colored green by its chromium content. In surveys made in Europe and the United States, green is the color most commonly associated with nature, life, health, youth, spring, hope and envy. In Europe and the U. S. green is associated with death, sickness, or the devil. In the Middle Ages and Renaissance, when the color of clothing showed the social status, green was worn by merchants, bankers. The Mona Lisa by Leonardo da Vinci wears green, showing she is not from a noble family, Green is also the traditional color of safety and permission, a green light means go ahead, a green card permits permanent residence in the United States. It is the most important color in Islam and it was the color of the banner of Muhammad, and is found in the flags of nearly all Islamic countries, and represents the lush vegetation of Paradise. It is also associated with the culture of Gaelic Ireland. Because of its association with nature, it is the color of the environmental movement, political groups advocating environmental protection and social justice describe themselves as part of the Green movement, some naming themselves Green parties. This has led to campaigns in advertising, as companies have sold green, or environmentally friendly. The word green comes from the Middle English and Old English word grene, which, like the German word grün, has the same root as the words grass and grow. It is from a Common Germanic *gronja-, which is reflected in Old Norse grænn, Old High German gruoni, ultimately from a PIE root *ghre- to grow. The first recorded use of the word as a term in Old English dates to ca. Latin with viridis also has a genuine and widely used term for green, related to virere to grow and ver spring, it gave rise to words in several Romance languages, French vert, Italian verde. Likewise the Slavic languages with zelenъ, Ancient Greek also had a term for yellowish, pale green – χλωρός, chloros, cognate with χλοερός verdant and χλόη the green of new growth

7.
CMYK color model
–
The CMYK color model is a subtractive color model, used in color printing, and is also used to describe the printing process itself. CMYK refers to the four used in some color printing, cyan, magenta, yellow. Though it varies by print house, press operator, press manufacturer, the K in CMYK stands for key because in four-color printing, cyan, magenta and yellow printing plates are carefully keyed, or aligned, with the key of the black key plate. Some sources suggest that the K in CMYK comes from the last letter in black and was chosen because B already means blue. Some sources claim this explanation, although useful as a mnemonic, is incorrect, the CMYK model works by partially or entirely masking colors on a lighter, usually white, background. The ink reduces the light that would otherwise be reflected, such a model is called subtractive because inks subtract brightness from white. In additive color models such as RGB, white is the combination of all primary colored lights. In the CMYK model, it is the opposite, white is the color of the paper or other background. To save cost on ink, and to produce deeper black tones, unsaturated and dark colors are produced by using black ink instead of the combination of cyan, magenta, with halftoning, a full continuous range of colors can be produced. To improve print quality and reduce moiré patterns, the screen for each color is set at a different angle. Common reasons for using black ink include, In traditional preparation of color separations, in some cases a black keyline was used when it served as both a color indicator and an outline to be printed in black. Because usually the black plate contained the keyline, the K in CMYK represents the keyline or black plate, also sometimes called the key plate. A combination of 100% cyan, magenta, and yellow inks soaks the paper with ink, making it slower to dry, causing bleeding, adding black ink absorbs more light and yields much better blacks. Using black ink is less expensive than using the corresponding amounts of colored inks. When a very dark area is desirable, a colored or gray CMY bedding is applied first, then a black layer is applied on top, making a rich, deep black. A black made with just CMY inks is sometimes called a composite black, the amount of black to use to replace amounts of the other ink is variable, and the choice depends on the technology, paper and ink in use. Processes called under color removal, under addition, and gray component replacement are used to decide on the final mix. CMYK or process color printing is contrasted with spot color printing, some printing presses are capable of printing with both four-color process inks and additional spot color inks at the same time

8.
Cyan
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It is evoked by light with a predominant wavelength of between 490–520 nm, between the wavelengths of blue and green. In the subtractive color system, or CMYK, which can be overlaid to produce all colors in paint and color printing, cyan is one of the colors, along with magenta, yellow. In the additive color system, or RGB color model, used to all the colors on a computer or television display, cyan is made by mixing equal amounts of green. Cyan is the complement of red, it can be made by the removal of red from white light, mixing red light and cyan light at the right intensity will make white light. The web color cyan is synonymous with aqua, other colors in the cyan color range are teal, turquoise, electric blue, aquamarine, and others described as blue-green. Its name is derived from the Ancient Greek κύανος, transliterated kyanos, meaning blue, dark blue enamel. It was formerly known as blue or cyan-blue, and its first recorded use as a color name in English was in 1879. Further origins of the name can be traced back to a dye produced from the cornflower. In most languages, cyan is not a color term. Reasons for why cyan is not linguistically acknowledged as a color term can be found in the frequent lack of distinction between blue and green in many languages. The web color cyan shown at right is a color in the RGB color model. In X11 colors, this color is called both cyan and aqua, in the HTML color list, this same color is called aqua. The web colors are more vivid than the used in the CMYK color system. To reproduce the web color cyan in inks, it is necessary to add some white ink to the printers cyan below, so when it is reproduced in printing, it is not a primary subtractive color. It is called aqua because it is a commonly associated with water. Cyan is also one of the inks used in four-color printing, along with magenta, yellow, and black. While both the secondary and the subtractive primary are called cyan, they can be substantially different from one another. Cyan printing ink can be saturated or less saturated than the RGB secondary cyan, depending on what RGB color space

9.
Magenta
–
Magenta is a color that is variously defined as purplish-red, reddish-purple, or mauvish-crimson. On computer screens, it is made by mixing equal amounts of blue, on color wheels of the RGB and CMY color models, it is located midway between red and blue. It is the color of green. It is one of the four colors of ink used in printing and by an inkjet printer, along with cyan, yellow. The tone of magenta used in printing is called printers magenta, Magenta was first introduced as the color of a new aniline dye called fuchsine, patented in 1859 by the French chemist François-Emmanuel Verguin. Its name was changed the year to magenta, to celebrate a victory of the French and Sardinian army at the Battle of Magenta on June 4,1859. The web color magenta is called fuchsia. Magenta is a color, meaning that it is not found in the visible spectrum of light. Rather, it is physiologically and psychologically perceived as the mixture of red and violet/blue light, with the absence of green. In the RGB color system, used to all the colors on a television or computer display, magenta is a secondary color, made by combining equal amounts of red. In this system, magenta is the color of green. In the CMYK color model, used in printing, it is one of the three primary colors, along with cyan and yellow, used to print all the rest of the colors. If magenta, cyan, and yellow are printed on top of each other on a page, in this model, magenta is the complementary color of green, and these two colors have the highest contrast and the greatest harmony. If combined, green and magenta ink will look dark gray or black, the magenta used in color printing, sometimes called process magenta, is a darker shade than the color used on computer screens. A purple hue in terms of theory, magenta is evoked by light having less power in green wavelengths than in blue/violet. In the Munsell color system, magenta is called red–purple, if the spectrum is wrapped to form a color wheel, magenta appears midway between red and violet. Violet and red, the two components of magenta, are at opposite ends of the spectrum and have very different wavelengths. The additive secondary color magenta, as noted above, is made by combining violet and red light at equal intensity, in optics, fuchsia and magenta are essentially the same color

10.
Yellow
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Yellow is the color between green and orange on the spectrum of visible light. It is evoked by light with a predominant wavelength of roughly 570–590 nm, in traditional color theory, used in painting, and in the subtractive color system, used in color printing, yellow is a primary color. In the RGB color model, used to create colors on television and computer screens, yellow is made by combining red, the word yellow comes from the Old English geolu, geolwe, meaning yellow, yellowish, derived from the Proto-Germanic word gelwaz yellow. It has the same Indo-European base, gʰel-, as the gold and yell. In Iran it has connotations of pallor/sickness, but also wisdom and it plays an important role in Asian culture, particularly in China, where it is seen as the color of happiness, glory, wisdom, harmony, and culture. The word yellow comes from the Old English geolu, geolwe, meaning yellow, yellowish and it has the same Indo-European base, gʰel-, as the words gold and yell, gʰel- means both bright and gleaming, and to cry out. The English term is related to other Germanic words for yellow, namely Scots yella, East Frisian jeel, West Frisian giel, Dutch geel, German gelb, and Swedish and Norwegian gul. According to the Oxford English Dictionary, the oldest known use of word in English is from The Epinal Glossary in 700. Yellow, in the form of yellow pigment made from clay, was one of the first colors used in prehistoric cave art. The cave of Lascaux has an image of a horse colored with yellow estimated to be 17,300 years old, in Ancient Egypt, yellow was associated with gold, which was considered to be imperishable, eternal and indestructible. The skin and bones of the gods were believed to be made of gold, the Egyptians used yellow extensively in tomb paintings, they usually used either yellow ochre or the brilliant orpiment, though it was made of arsenic and was highly toxic. A small paintbox with orpiment pigment was found in the tomb of King Tutankhamun, men were always shown with brown faces, women with yellow ochre or gold faces. The ancient Romans used yellow in their paintings to represent gold and it is found frequently in the murals of Pompeii. During the Post-Classical period, yellow became firmly established as the color of Judas Iscariot, from this connection, yellow also took on associations with envy, jealousy and duplicity. The tradition started in the Renaissance of marking non-Christian outsiders, such as Jews, in 16th century Spain, those accused of heresy and who refused to renounce their views were compelled to come before the Spanish Inquisition dressed in a yellow cape. The color yellow has been associated with moneylenders and finance. The National Pawnbrokers Associations logo depicts three golden spheres hanging from a bar, referencing the three bags of gold that the saint of pawnbroking, St. Nicholas, holds in his hands. Additionally, the symbol of three golden orbs is found in the coat of arms of the House of Medici, a fifteenth century Italian dynasty of bankers and lenders

11.
Black
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Black is the darkest color resulting from the absence or complete absorption of light. Like white and grey, it is a color, literally a color without hue. It is one of the four colors in the CMYK color model, along with cyan, yellow. Black is often used to represent darkness, it is the symbolic opposite of white, Black was one of the first colors used by artists in neolithic cave paintings. In the 14th century, it began to be worn by royalty and it became the color worn by English romantic poets, businessmen and statesmen in the 19th century, and a high fashion color in the 20th century. In the Roman Empire, it became the color of mourning, according to surveys in Europe and North America, it is the color most commonly associated with mourning, the end, secrets, magic, force, violence, evil, and elegance. More distant cognates include Latin flagrare, and Ancient Greek phlegein, the Ancient Greeks sometimes used the same word to name different colors, if they had the same intensity. Kuanos could mean both dark blue and black, the Ancient Romans had two words for black, ater was a flat, dull black, while niger was a brilliant, saturated black. Ater has vanished from the vocabulary, but niger was the source of the country name Nigeria the English word Negro, old High German also had two words for black, swartz for dull black and blach for a luminous black. These are parallelled in Middle English by the terms swart for dull black, swart still survives as the word swarthy, while blaek became the modern English black. In heraldry, the used for the black color is sable, named for the black fur of the sable. Black was one of the first colors used in art, the Lascaux Cave in France contains drawings of bulls and other animals drawn by paleolithic artists between 18,000 and 17,000 years ago. They began by using charcoal, and then made more vivid black pigments by burning bones or grinding a powder of manganese oxide, for the ancient Egyptians, black had positive associations, being the color of fertility and the rich black soil flooded by the Nile. It was the color of Anubis, the god of the underworld, who took the form of a black jackal, and offered protection against evil to the dead. For the ancient Greeks, black was also the color of the underworld, separated from the world of the living by the river Acheron and those who had committed the worst sins were sent to Tartarus, the deepest and darkest level. In the center was the palace of Hades, the king of the underworld, Black was one of the most important colors used by ancient Greek artists. In the 6th century BC, they began making pottery and later red figure pottery. In black-figure pottery, the artist would paint figures with a clay slip on a red clay pot

12.
HSL and HSV
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HSL and HSV are the two most common cylindrical-coordinate representations of points in an RGB color model. The two representations rearrange the geometry of RGB in an attempt to be intuitive and perceptually relevant than the cartesian representation. Developed in the 1970s for computer applications, HSL and HSV are used today in color pickers, in image editing software. HSL stands for hue, saturation, and lightness, and is often called HLS. HSV stands for hue, saturation, and value, and is often called HSB. A third model, common in computer applications, is HSI. However, while typically consistent, these definitions are not standardized, note that while hue in HSL and HSV refers to the same attribute, their definitions of saturation differ dramatically. As a result, each unique RGB device has unique HSL and HSV absolute color spaces to accompany it, other more computationally intensive models, such as CIELAB or CIECAM02, are said to better achieve these goals. In each geometry, the vertical axis comprises the neutral, achromatic, or gray colors, ranging from black at lightness 0 or value 0, the bottom, to white at lightness 1 or value 1. These saturated colors have lightness ½ in HSL, while in HSV they have value 1, mixing these pure colors with black—producing so-called shades—leaves saturation unchanged. In HSL, saturation is also unchanged by tinting with white, in HSV, tinting alone reduces saturation. Confusingly, such diagrams usually label this radial dimension saturation, blurring or erasing the distinction between saturation and chroma, as described below, computing chroma is a helpful step in the derivation of each model. Most televisions, computer displays, and projectors produce colors by combining red, green, furthermore, neither additive nor subtractive color models define color relationships the same way the human eye does. For example, imagine we have an RGB display whose color is controlled by three sliders ranging from 0–255, one controlling the intensity of each of the red, green, consequently, these models and similar ones have become ubiquitous throughout image editing and graphics software since then. Some of their uses are described below, nonetheless, it is worth reviewing those definitions before leaping into the derivation of our models. Hue The attribute of a visual sensation according to which an area appears to be similar to one of the colors, red, yellow, green. Radiance The radiant power of passing through a particular surface per unit solid angle per unit projected area. Luminance The radiance weighted by the effect of each wavelength on a human observer

13.
Hue
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Orange and violet are the other hues, for a total of six, as in the rainbow, red, orange, yellow, green, blue, violet. The other color appearance parameters are colorfulness, chroma, saturation, lightness, usually, colors with the same hue are distinguished with adjectives referring to their lightness and/or colorfulness, such as with light blue, pastel blue, vivid blue. Exceptions include brown, which is a dark orange, in painting color theory, a hue refers to a pure color—one without tint or shade. A hue is an element of the color wheel, hues are first processed in the brain in areas in the extended V4 called globs. Hue is the component of the polar representation, while chroma is the radial component. Specifically, in CIELAB h a b = a t a n 2, while, analogously, in CIELUV h u v = a t a n 2 = a t a n 2, where, atan2 is a two-argument inverse tangent. Preucil describes a color hexagon, similar to a trilinear plot described by Evans, Hanson, and Brewer, to place red at 0°, green at 120°, and blue at 240°, h r g b = a t a n 2. Equivalently, one may solve tan ⁡ =3 ⋅2 ⋅ R − G − B, Preucil used a polar plot, which he termed a color circle. Using R, G, and B, one may compute hue angle using the scheme, determine which of the six possible orderings of R, G. Note that in case the formula contains the fraction M − L H − L, where H is the highest of R, G, and B, L is the lowest. This is referred to as the Preucil hue error and was used in the computation of mask strength in photomechanical color reproduction, the formulae used are those in the table above. The hues exhibited by caramel colorings and beers are fairly limited in range, the Linner hue index is used to quantify the hue of such products. Replacements are often used for chromium, cadmium and alizarin, dominant wavelength is a physical analog to the perceptual attribute hue. On a chromaticity diagram, a line is drawn from a point through the coordinates of the color in question. There are two ways in which hue difference is quantified. The first is the difference between the two hue angles. The symbol for expression of hue difference is Δ h a b in CIELAB. The other is computed as the total color difference after Lightness and Chroma differences have been accounted for, its symbol is Δ H a b ∗ in CIELAB

14.
Colorfulness
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Colorfulness or saturation in colorimetry and color theory refers to the perceived intensity of a specific color. Colorfulness is the visual sensation according to which the color of an area appears to be more or less chromatic. Chroma is the relative to the brightness of a similarly illuminated area that appears to be white or highly transmitting. Therefore, chroma should not be confused with colorfulness, saturation is the colorfulness of a color relative to its own brightness. A highly colorful stimulus is vivid and intense, while a less colorful stimulus appears more muted, with no colorfulness at all, a color is a “neutral” gray. Any color can be described using three color appearance parameters — colorfulness, lightness, and hue, saturation is one of three coordinates in the HSL and HSV color spaces. The saturation of a color is determined by a combination of light intensity, the purest color is achieved by using just one wavelength at a high intensity, such as in laser light. If the intensity drops, then as a result the saturation drops, to desaturate a color of given intensity in a subtractive system, one can add white, black, gray, or the hues complement. CIELUV The chroma normalized by the lightness, s u v = C u v ∗ L ∗ =132 +2 where is the chromaticity of the white point, and chroma is defined below. Nevertheless, this provides a reasonable predictor of saturation. S a b = C a b ∗ C a b ∗2 + L ∗2100 % where Sab is the saturation, L* the lightness and C*ab is the chroma of the color. CIECAM02 The square root of the colorfulness divided by the brightness, M is proportional to the chroma C, thus the CIECAM02 definition bears some similarity to the CIELUV definition. An important difference is that the CIECAM02 model accounts for the conditions through the parameter FL. Different color spaces, such as CIELAB or CIELUV may be used, the naïve definition of saturation does not specify its response function. However, both color spaces are nonlinear in terms of perceived color differences. It is also possible—and sometimes desirable—to define a quantity that is linearized in term of the psychovisual perception. The transformation of to is given by, C a b ∗ = a ∗2 + b ∗2 h a b = arctan ⁡ b ∗ a ∗ and analogously for CIE L*C*h. The chroma in the CIE L*C*h and CIE L*C*h coordinates has the advantage of being more psychovisually linear, and therefore, chroma in CIE1976 L*a*b* and L*u*v* color spaces is very much different from the traditional sense of saturation

15.
Brightness
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Brightness is an attribute of visual perception in which a source appears to be radiating or reflecting light. In other words, brightness is the perception elicited by the luminance of a visual target and it is not necessarily proportional to luminance. This is a subjective attribute/property of an object being observed and one of the color appearance parameters of color appearance models, brightness refers to an absolute term and should not be confused with Lightness. The adjective bright derives from an Old English beorht with the same meaning via metathesis giving Middle English briht, the word is from a Common Germanic *berhtaz, ultimately from a PIE root with a closely related meaning, *bhereg- white, bright. Brightness was formerly used as a synonym for the term luminance. As defined by the US Federal Glossary of Telecommunication Terms, brightness should now be used only for non-quantitative references to physiological sensations and perceptions of light, a given target luminance can elicit different perceptions of brightness in different contexts, see, for example, Whites illusion. With regard to stars, brightness is quantified as apparent magnitude, brightness is, at least in some respects, the antonym of darkness. The United States Federal Trade Commission has assigned a meaning to brightness when applied to lamps. When appearing on light bulb packages, brightness means Luminous flux, Luminous flux is the total amount of light coming from a source, such as a lighting device. Luminance, the meaning of brightness, is the amount of light per solid angle coming from an area. The table below shows the ways of indicating the amount of light. The term brightness is used in discussions of sound timbres. Luma Luminance Luminosity Media related to brightness at Wikimedia Commons Poyntons Color FAQ

16.
Color
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Color or colour is the characteristic of human visual perception described through color categories, with names such as red, yellow, purple, or blue. This perception of color derives from the stimulation of cells in the human eye by electromagnetic radiation in the spectrum of light. Color categories and physical specifications of color are associated with objects through the wavelength of the light that is reflected from them and this reflection is governed by the objects physical properties such as light absorption, emission spectra, etc. By defining a color space, colors can be identified numerically by coordinates, there may also be more than three color dimensions in other color spaces, such as in the CMYK color model, wherein one of the dimensions relates to a colours colorfulness). The photo-receptivity of the eyes of species also varies considerably from our own. Honeybees and bumblebees for instance have trichromatic color vision sensitive to ultraviolet but is insensitive to red, papilio butterflies possess six types of photoreceptors and may have pentachromatic vision. The most complex color vision system in the kingdom has been found in stomatopods with up to 12 spectral receptor types thought to work as multiple dichromatic units. The science of color is sometimes called chromatics, colorimetry, or simply color science and it includes the perception of color by the human eye and brain, the origin of color in materials, color theory in art, and the physics of electromagnetic radiation in the visible range. Electromagnetic radiation is characterized by its wavelength and its intensity, when the wavelength is within the visible spectrum, it is known as visible light. Most light sources emit light at different wavelengths, a sources spectrum is a distribution giving its intensity at each wavelength. Although the spectrum of light arriving at the eye from a given direction determines the color sensation in that direction, in each such class the members are called metamers of the color in question. The table at right shows approximate frequencies and wavelengths for various pure spectral colors, the wavelengths listed are as measured in air or vacuum. A common list identifies six main bands, red, orange, yellow, green, blue, Newtons conception included a seventh color, indigo, between blue and violet. It is possible that what Newton referred to as blue is nearer to what today is known as cyan, the color of an object depends on both the physics of the object in its environment and the characteristics of the perceiving eye and brain. Some objects not only light, but also transmit light or emit light themselves. This effect is known as color constancy, opaque objects that do not reflect specularly have their color determined by which wavelengths of light they scatter strongly. If objects scatter all wavelengths with roughly equal strength, they appear white, if they absorb all wavelengths, they appear black. Opaque objects that reflect light of different wavelengths with different efficiencies look like mirrors tinted with colors determined by those differences

17.
Lightness
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In colorimetry and color theory, lightness, also known as value or tone, is a representation of variation in the perception of a color or color spaces brightness. It is one of the color appearance parameters of any color appearance model, various color models have an explicit term for this property. The Munsell color model uses the value, while the HSL color model, HCL color space. The HSV model uses the value a little differently, a color with a low value is nearly black. In subtractive color value changes can be achieved by adding black or white to the color, chiaroscuro and Tenebrism both take advantage of dramatic contrasts of value to heighten drama in art. Artists may also employ shading, subtle manipulation of value, the Munsell value has long been used as a perceptually uniform lightness scale. A question of interest is the relationship between the Munsell value scale and the relative luminance, aware of the Weber–Fechner law, Munsell remarked Should we use a logarithmic curve or curve of squares. The remainder of section is a chronology of lightness approximations. – Munsells V runs from 0 to 10, while Y typically runs from 0 to 100, typically, the relative luminance is normalized so that the reference white has a tristimulus value of Y =100. Since the reflectance of magnesium oxide relative to the perfect reflecting diffuser is 97. 5%,1943 Newhall, Nickerson, and Judd prepare a report for the Optical Society of America. They suggest a quintic parabola, Y =1.221,9 V −0.231,11 V2 +0.239,51 V3 −0.021,009 V4 +0.000,840,4 V5. 1943 Using Table II of the O. S. A, report, Moon and Spencer express the value in terms of the relative luminance, V =50.426 =1.4 Y0.426. 1944 Saunderson and Milner introduce a constant in the previous expression. Later, Jameson and Hurvich claim that this corrects for simultaneous contrast effects, V =2.357 Y0.343 −1.52. 1955 Ladd and Pinney of Eastman Kodak are interested in the Munsell value as a uniform lightness scale for use in television. After considering one logarithmic and five power-law functions, they relate value to reflectance by raising the reflectance to the power of 0.352, V =2.217 Y0.352 −1.324. Realizing this is close to the cube root, they simplify it to. 1958 Glasser et al. define the lightness as ten times the Munsell value,1964 Wyszecki simplifies this to, W ⋆ =25 Y1 /3 −17

18.
Tints and shades
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In color theory, a tint is the mixture of a color with white, which increases lightness, and a shade is the mixture of a color with black, which reduces lightness. A tone is produced either by the mixture of a color with gray, mixing a color with any neutral color reduces the chroma, or colorfulness, while the hue remains unchanged. When mixing colored light, the mixture of spectrally balanced red, green and blue is always white. When we mix colorants, such as the pigments in paint mixtures and this moves the mixed color toward a neutral color—a gray or near-black. Lights are made brighter or dimmer by adjusting their brightness, or energy level, in painting, lightness is adjusted through mixture with white, black or a colors complement. It is common among some painters to darken a paint color by adding black paint—producing colors called shades—or to lighten a color by adding white—producing colors called tints. However, this is not always the best way for representational painting, for instance, darkening a color by adding black can cause colors such as yellows, reds and oranges, to shift toward the greenish or bluish part of the spectrum. Lightening a color by adding white can cause a shift towards blue when mixed with reds and oranges. When lightening a color this hue shift can be corrected with the addition of an amount of an adjacent color to bring the hue of the mixture back in line with the parent color

19.
Color theory
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In the visual arts, color theory or colour theory is a body of practical guidance to color mixing and the visual effects of a specific color combination. There are also definitions of colors based on the wheel, primary color, secondary color. From there it developed as an independent artistic tradition with only superficial reference to colorimetry, the foundations of pre-20th-century color theory were built around pure or ideal colors, characterized by sensory experiences rather than attributes of the physical world. This has led to a number of inaccuracies in traditional color theory principles that are not always remedied in modern formulations. The most important problem has been a confusion between the behavior of light mixtures, called additive color, and the behavior of paint, ink, dye, or pigment mixtures, called subtractive color. This problem arises because the absorption of light by material substances follows different rules from the perception of light by the eye, thus, the visual impact of yellow vs. blue hues in visual design depends on the relative lightness and saturation of the hues. e. Any three real primary colors of light, paint or ink can mix only a range of colors, called a gamut. Color theory was formulated in terms of three primary or primitive colors—red, yellow and blue —because these colors were believed capable of mixing all other colors. This color mixing behavior had long known to printers, dyers and painters. Subsequent research anchored these primary colors in the responses to light by three types of color receptors or cones in the retina. It also created the dyes and chemical processes necessary for color photography, a wider range of color can be obtained with the addition of other colors to the printing process, such as in Pantones Hexachrome printing ink system, among others. For the mixing of colored light, Isaac Newtons color wheel is used to describe complementary colors. Newton offered as a conjecture that colors exactly opposite one another on the hue circle cancel out each others hue, this concept was demonstrated more thoroughly in the 19th century. A key assumption in Newtons hue circle was that the fiery or maximum saturated hues are located on the circumference of the circle, while achromatic white is at the center. These contrasts form the basis of Chevreuls law of color contrast, thus, a piece of yellow fabric placed on a blue background will appear tinted orange, because orange is the complementary color to blue. However, when complementary colors are based on definition by light mixture. This discrepancy becomes important when color theory is applied across media, digital color management uses a hue circle defined according to additive primary colors, as the colors in a computer monitor are additive mixtures of light, not subtractive mixtures of paints. One reason the artists primary colors work at all is that the imperfect pigments being used have sloped absorption curves, a pigment that is pure red at high concentrations can behave more like magenta at low concentrations

20.
White
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White is an achromatic color, a color without hue. An incoming light to the eye that stimulates all its three types of color sensitive cone cells in nearly equal amounts results in white. White is one of the most common colors in nature, the color of sunlight, snow, milk, chalk, limestone, in many cultures white represents or signifies purity, innocence, and light, and is the symbolic opposite of black, or darkness. According to surveys in Europe and the United States, white is the color most often associated with perfection, the good, honesty, cleanliness, the beginning, the new, neutrality, and exactitude. In ancient Egypt and ancient Rome, priestesses wore white as a symbol of purity, in the Middle Ages and Renaissance a white unicorn symbolized chastity, and a white lamb sacrifice and purity, the widows of kings dressed in white rather than black as the color of mourning. It was also used in 20th century modern architecture as a symbol of modernity, simplicity. White is an important color for almost all world religions, the Pope, the head of the Roman Catholic Church, has worn white since 1566, as a symbol of purity and sacrifice. In Islam, and in the Shinto religion of Japan, it is worn by pilgrims, in Western cultures and in Japan, white is the most common color for wedding dresses, symbolizing purity and virginity. In many Asian cultures, white is also the color of mourning, the white color on television screens and computer monitors is created with the RGB color model by mixing red, green and blue light at equal intensities. The word white continues Old English hwīt, ultimately from a Common Germanic *χwītaz also reflected in OHG wîz, ON hvítr, the root is ultimately from Proto-Indo-European language *kwid-, surviving also in Sanskrit śveta to be white or bright and Slavonic světŭ light. The Icelandic word for white, hvítur, is derived from the Old Norse form of the word hvítr. Common Germanic also had the word *blankaz, borrowed into Late Latin as *blancus, the antonym of white is black. Some non-European languages have a variety of terms for white. The Inuit language has seven different words for seven different nuances of white, Japanese has six different words, depending upon brilliance or dullness, or if the color is inert or dynamic. White was one of the first colors used in art, the Lascaux Cave in France contains drawings of bulls and other animals drawn by paleolithic artists between 18,000 and 17,000 years ago. Paleolithic artists used calcite or chalk, they sometimes as a background, sometimes as a highlight, along with charcoal and red, in ancient Egypt, white was connected with the goddess Isis. The priests and priestesses of Isis dressed only in white linen, in Greece and other ancient civilizations, white was often associated with mothers milk. In Greek mythology, the chief god Zeus was nourished at the breast of the nymph Amalthea, in the Talmud, milk was one of four sacred substances, along with wine, honey, and the rose

21.
Grey
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Grey or gray is an intermediate color between black and white. It is a neutral or achromatic color, meaning literally that it is a color without color and this means that there are equal components of red, green, and blue. The variations in intensity of these colors uniformly produce different shades of grey and it is the color of a cloud-covered sky, of ash and of lead. The first recorded use of grey as a name in the English language was in AD700. Grey is the dominant spelling in European and Commonwealth English, although remained in common usage in the UK until the second half of the 20th century. Gray has been the preferred American spelling since approximately 1825, although grey is an accepted variant, in Europe and the United States, surveys show that grey is the color most commonly associated with neutrality, conformity, boredom, uncertainty, old age, indifference, and modesty. Only one percent of respondents chose it as their favorite color, Grey comes from the Middle English grai or grei, from the Anglo-Saxon graeg, and is related to the Dutch grauw and grijs and German grau. The first recorded use of grey as a name in the English language was in AD700. In antiquity and the Middle Ages, grey was the color of undyed wool, and thus was the color most commonly worn by peasants and the poor. It was also the color worn by monks of the Franciscan order, Cistercian Order, Franciscan monks in England and Scotland were commonly known as the Grey friars, and that name is now attached to many places in Great Britain. During the Renaissance and the Baroque, grey began to play an important role in fashion, Black became the most popular color of the nobility, particularly in Italy, France, and Spain, and grey and white were harmonious with it. Grey was also used for the drawing of oil paintings. The painting would first be composed in grey and white, and then the colors, made with thin transparent glazes, the grisaille beneath would provide the shading, visible through the layers of color. Sometimes the grisaille was simply left uncovered, giving the appearance of carved stone, Grey was a particularly good background color for gold and for skin tones. It became the most common background for the portraits of Rembrandt Van Rijn and for many of the paintings of El Greco, the palette of Rembrandt was composed almost entirely of somber colors. Over this he put a layer of glaze made of mixture of blue smalt, red ochre. Using these ingredients and many others, he made greys which had, according to art historian Philip Ball, the warm, dark and rich greys and browns served to emphasize the golden light on the faces in the paintings. Grey became a fashionable color in the 18th century, both for womens dresses and for mens waistcoats and coats

22.
Pastel
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A pastel is an art medium in the form of a stick, consisting of pure powdered pigment and a binder. The pigments used in pastels are the same as used to produce all colored art media, including oil paints. The color effect of pastels is closer to the natural dry pigments than that of any other process, Pastels have been used by artists since the Renaissance, and gained considerable popularity in the 18th century, when a number of notable artists made pastel their primary medium. An artwork made using pastels is called a pastel, Pastel used as a verb means to produce an artwork with pastels, as an adjective it means pale in color. Pastel sticks or crayons consist of powdered pigment combined with a binder. The exact composition and characteristics of an individual pastel stick depends on the type of pastel and it also varies by individual manufacturer. Dry pastels have historically used binders such as gum arabic and gum tragacanth, methyl cellulose was introduced as a binder in the twentieth century. Often a chalk or gypsum component is present and they are available in varying degrees of hardness, the softer varieties being wrapped in paper. Some pastel brands use pumice in the binder to abrade the paper, dry pastel media can be subdivided as follows, Soft pastels, This is the most widely used form of pastel. The sticks have a portion of pigment and less binder. The drawing can be readily smudged and blended, but it results in a proportion of dust. White chalk may be used as a filler in producing pale, Pan Pastels, These are formulated with a minimum of binder in flat compacts and applied with special Soft micropore sponge tools. A 21st-century invention, Pan Pastels can be used for the painting or in combination with soft. Hard pastels, These have a portion of binder and less pigment. These can be used with other pastels for drawing outlines and adding accents, hard pastels are traditionally used to create the preliminary sketching out of a composition. However, the colors are brilliant and are available in a restricted range in contrast to soft pastels. Pastel pencils, These are pencils with a pastel lead and they are useful for adding fine details. In addition, pastels using a different approach to manufacture have been developed, Oil pastels, These have a soft, buttery consistency and they are dense and fill the grain of paper and are slightly more difficult to blend than soft pastels, but do not require a fixative

23.
Azure (color)
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Azure is a variation of blue that is often described as the color of the sky on a clear day. On the RGB color wheel, azure is defined as the color at 210 degrees, in the RGB color model, used to create all the colors on a television or computer screen, azure is created by adding a little green light to blue light. The complementary color of azure is neon orange, in the X11 color system which became a standard for early web colors, azure is depicted as a pale cyan. The color azure ultimately takes its name from the blue mineral lapis lazuli. The name of the came to be associated with its color. Azure also describes the color of the mineral azurite, both in its form and as a pigment in various paint formulations. In order to preserve its deep color, azurite was ground coarsely, fine-ground azurite produces a lighter, washed-out color. Traditionally, the pigment was considered unstable in oil paints, and was isolated from other colors. Modern investigation of old paintings, however, shows that the pigment is very stable unless exposed to sulfur fumes, the use of the term spread through the practice of heraldry, where azure represents a blue color in the system of tinctures. In engravings, it is represented as a region of horizontal lines. In practice, azure has been represented by any number of shades of blue, in later heraldic practice a lighter blue, called bleu celeste, is sometimes specified. All of the colors shown below in the variations of azure are referenced as having a hue code of between 195 and 225, signifying that these colors are tones of azure. The only exception, as noted below, is the web color azure which, displayed at right is the web color called azure, in actuality it is a pale pastel tint of cyan, as can be ascertained by noting its hue angle of 180 degrees. In an artistic context, this color would be called azure mist, the web color Alice blue is a pale tint of azure. Displayed at right is the web color sky blue. Baby blue is known as one of the pastel colors and this color is associated with baby boys in Western culture. The first recorded use of blue as a color name in English was in 1892. Displayed at right is the web color sky blue, the first recorded use of sky blue as a color name in English was in 1728 in the Cyclopædia of Ephraim Chambers

24.
Sky blue
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Sky blue is the name of a colour that resembles the colour of the sky at noon. The entry for sky-blue in Murrays New English Dictionary reports a first sighting of the term in the article on silver in Ephraim Chamberss Cyclopaedia of 1728, however, many writers had used the term sky blue to name a colour before Chambers. For example, we find sky blue in A Collection of Voyages and Travels,2, p.322, where John Nieuhoff describes certain flowers, they are of a lovely sky blue colour, and yellow in the middle. The sense of colour may have been first used in 1585 in a book by Nicolas de Nicolay where he stated the tulbant of the merchant must be skie coloured. Displayed at right is the web colour sky blue, Celeste is the colloquial name for the pale turquoise blue colour associated with Italian bicycle manufacturer Bianchi S. p. A and sometimes known as Bianchi Green. In Italian, as the name indicates, it is an attempt to reproduce the colour of clear skies, in English, this colour may also be referred to as Italian sky blue. Bleu celeste is a rarely occurring tincture in heraldry and this tincture is sometimes also called ciel or simply celeste. It is depicted in a lighter shade than the range of shades of the more traditional tincture azure, Bianchi bicycles are traditionally painted celeste, also known as Bianchi Green. Contradictory myths say celeste is the colour of the Milan sky, the eye colour of a queen for whom Edoardo Bianchi made a bicycle. The exact shade of turquoise used by the company has varied over time, in Anglophone countries Celeste is sometimes reported as Pantone -#332, and with various other shades. Displayed at right is the web colour sky blue. It is close in shade to baby blue, displayed at right is the colour medium sky blue. This is the colour that is called sky blue in Crayola crayons and this colour was formulated by Crayola in 1958. Sky blue appears in the 32,48,64,96 and 120 packs of crayons, displayed at right is the colour vivid sky blue. Deep sky blue is an azure-cyan colour associated with sky blue. Deep sky blue is a web colour and this colour is the colour on the colour wheel halfway between azure and cyan. The traditional name for this colour is Capri, the first use of Capri as a colour name in English was in 1920. Specifically, the colour Capri is named after the colour of the Blue Grotto on the island of Capri. as it appears on a sunny day

25.
Periwinkle (color)
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Periwinkle is a color in the blue and violet family. Its name is derived from the lesser periwinkle or myrtle herb which bears flowers of the same color, the color periwinkle is also called lavender blue. The color periwinkle may be considered a tint of blue or a pastel blue. The first recorded use of periwinkle as a name in English was in 1922. Periwinkle blue is the color for esophageal and stomach cancer awareness ribbons and it is also the color for pulmonary hypertension awareness ribbons. The downvote of the popular website Reddit is identified as periwinkle, periwinkle was added to the Crayola palette in 1958. Periwinkle is the name of Tinker Bells sister in the film Tinker Bell, in the film Snatch, Brad Pitt, talking about his mother, says, Right. And shes terrible partial to the blue, boys. Have I made myself clear, boys, in Harry Potter and the Goblet of Fire, Hermione wears a periwinkle blue dress to the Yule Ball. In the Late 1990s the Anaheim Angels changed their uniforn to include this color Lavender Light blue List of colors A description of the Vinca minor species

26.
Vinca minor
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Other vernacular names used in cultivation include small periwinkle, common periwinkle, and sometimes in the United States, myrtle or creeping myrtle. The leaves are evergreen, opposite, 2–4.5 centimetres long and 1–2.5 centimetres broad, glossy green with a leathery texture. The fruit is a pair of follicles 2.5 centimetres long, containing numerous seeds, the closely related species Vinca major is similar, but larger in all parts, and also has relatively broader leaves with a hairy margin. The species is grown as a groundcover in temperate gardens for its evergreen foliage, spring and summer flowers, ease of culture. It was once planted in cemeteries in parts of the American South. The species has few pests or diseases outside its range and is widely naturalised and classified as an invasive species in parts of North America. Invasion can be restricted by removal of rooting stems in spring, once established, it is difficult to eradicate, as its waxy leaves shed most water-based herbicide sprays. Removal involves cutting, followed by application of concentrated glyphosate or triclopyr to the cut stems. Repeated chemical treatments may be necessary, along with digging up the roots where feasible, there are numerous cultivars, with different flower colours and variegated foliage. Many have a less vigorous habit than the species, and are more suitable for smaller gardens. Vinca minor contains more than 50 alkaloids, including vincamine, vinpocetine is a semisynthetic derivative alkaloid of vincamine. The color name periwinkle is derived from the flower, flora Europaea, Vinca minor distribution Morphology and ecology of Vinca minor Borealforest, Vinca minor Vinca minor Common periwinkle Blamey, M. & Grey-Wilson, C. Flora of Britain and Northern Europe, new RHS Dictionary of Gardening 4,665. Detailed technical description Encyclopedia of Life database entry Traditional Medicine Uses, Vinca minor

In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's …

Wavelength is decreased in a medium with slower propagation.

A wave on a line of atoms can be interpreted according to a variety of wavelengths.

Pattern of light intensity on a screen for light passing through two slits. The labels on the right refer to the difference of the path lengths from the two slits, which are idealized here as point sources.